Understanding the Central & Peripheral Nervous Systems - Yoffie Life
That the brain and peripheral nervous systems interact is no surprise to the relationships among the brain, peripheral responses, and behavior. psychophysiology and neuroscience, but it also depicts the ways in which. The central nervous system (CNS) consists of the brain, spinal cord, There are also two types of glial cells in the PNS – Schwann cells They serve as scaffolding to guide neurons to their proper destination during brain. Start studying Relationship between CNS and PNS. Learn vocabulary, terms, and more with flashcards, games, and other study tools.
And then the brain stem itself is divided into three smaller parts. The very top part of the brain stem that connects to the cerebrum, is called the mid brain, mid brain. And the middle part that's just below the mid brain we call the pons, P-O-N-S, for pons. Under the pons, and the part that actually connects to the spinal cord, is called the medulla, or medulla, or sometimes people use a longer name of medulla oblongata.
And then the last part, but not the least part of the brain, is this big part in the back. It's behind the brain stem and connected to the brain stem.
And this, we call the cerebellum. Now sometimes brain structures are referred to by the names of the structure that they develop from in the embryo.
So here's a picture of the human embryo and it's developing it's brain here. And this very front part is called the fore brain or it has a longer name of prosencephalon. This part behind the fore brain is called the mid brain and it also has a longer name called the mesencephalon.
And then the part behind the mid brain is called the hind brain, hind brain, and it also has a longer name of the rhombencephalon. So the fore brain is going to become the cerebrum. The mid brain is going to become the mid brain. Just this part of the brain stem, up top.
And then the hind brain will become the rest of the brain. The pons, the medulla, and the cerebellum. So just in case you hear people referring to structures in the brain by these names, that's where those names come from. They're from the developing nervous system. Here's a drawing of the spinal cord. This kind of long tube that runs down the spine.
And there's a number of structures coming out of the spinal cord that I'll talk about next.
The difference between centre and periphery
So those are the parts that make up most of the central nervous system, and everything that's not in the central nervous system we call the peripheral nervous system. And the central nervous system is called that because it's kind of in the center of the body and then the peripheral nervous system is called that because it's going to go out all over the rest of the body. The peripheral nervous system consists of two types of structures. The first are called nerves.
Let me just underline this nerve right here. And these are the long stringy structures that are going to go all over the body. And nerves carry the axons of neurons. The second main structure of the peripheral nervous system are called ganglion.
Ganglion is singular and ganglia is pleural. And ganglia are these lumps that are attached to nerves and they contain the somas of neurons. Now let me just draw that a little differently over on this picture of the spinal cord that have these nerves coming out of it. So here's one of these lumps, one of these ganglia that contains the somas of some of the neurons in the peripheral nervous system and some of these axons traveling through these nerves are going to be carrying information in to the central nervous system from the periphery.
So they're going to bring information in this way from out here in the periphery. And when they do that, we call those afferent neurons, afferent neurons carry information in to the central nervous system.
Now other neurons are going to have axons that carry information in the opposite direction. So they're going to carry information away from the central nervous system out into the periphery. And neurons whose axons carry information away from the central nervous system we call efferent neurons.
Central nervous system: Structure, function, and diseases
Now there are lots of these nerves that are going all over the body. And you can divide them up in a few different ways. But we usually start by dividing them into the cranial nerves which are nerves that exit the skull or the cranium.
The spinal cord responds with a reflex to pull your hand away from the stove quickly.
If the signal went all the way to your brain, by the time your body responded, there might already be tremendous damage to your hand. Therefore, the spinal cord sends the signal for the reflexive response so you can pull your hand away from the stove before your brain senses the danger and pain.
Take a moment and imagine a classroom. First, picture the classroom with no teacher. There are several students, all picking up interesting bits of information about their environment, but with no teacher to help guide them.
Now picture the same classroom with a teacher but no students. For an effective classroom setting, you need both the students, hungry for knowledge and sharing all sorts of insights; and a teacher, who can help guide and focus the students toward productive activities.
The nervous system is much like the classroom. Because the nervous system is so large and spans the entire body, if you experience any kind of pain, injury, or condition anywhere in the body, it likely will affect your nervous system. If someone experiences a concussion, which is trauma to the head, several brain cells quite literally die. Those brain cells will never regenerate, so the capacity for the CNS to receive and process information is compromised.
Similarly, if you develop tendinitis in your shoulder, the inflammation though it comes with the best intentions of healing the injury increases the pressure inside the joint.
All joints are designed to have a certain amount of space so all the bones, tendons, nerves, and muscles have room to function properly. Since the PNS has nerves that pass through all your joints, if there is too much compression in the joint, a nerve may become compressed or impinged. Compression of a nerve is very painful and can lead to irreversible damage.
Structure of the nervous system
Swelling triggers a buildup of connective tissue which becomes hard or dehydrated to protect the joint from further injury. This connective tissue is sometimes referred to as scar tissue. Scar tissue tends to be very strong and inflexible. Scar tissue that surrounds a nerve can lead to a condition called nerve entrapment.
When a nerve is entrapped, the scar tissue and adhesions prevent signals from being transferred through the nerve. When in perfect alignment, the body is the healthiest, most efficient version of itself. All the joints have the proper amount of space, and the muscles are proportionately strong and stretched.